1. Field of the Invention
The present invention relates to a monitoring system, and more specifically relates to a monitoring system that detects an intruding object in a monitoring area, to generate a stop signal for stopping an operation of an external device.
2. Description of Related Art
An area monitoring sensor is a safety device which optically detects an intruding object, such as a person, that has intruded into a monitoring area, to generate a stop signal for stopping an operation of an external device such as a machine tool (e.g., Unexamined Japanese Patent Publication Nos. 2009-296087 and 2009-294734).
For example, the area monitoring sensor is provided with a light projection part that generates detection light, a scanning part that performs a scan with the detection light in a circumferential direction about a rotational axis, and a light reception part that receives the detection light reflected by a target to generate a detection signal. The intruding object is detected by obtaining a distance to the target based on the detection signal and specifying a two-dimensional position of the target from the distance to the target and a scanning angle of the detection light.
Area setting information to specify the monitoring area and operation setting information to specify an operating condition for area monitoring are created by use of a terminal device such as a personal computer. The terminal device generates setting data made up of the area setting information and the operation setting information based on a user operation, and transmits the setting data to the area monitoring sensor. The area monitoring sensor detects intrusion based on the setting data received from the terminal device.
In such a monitoring system as described above, it is considered that a camera for photographing the monitoring area is provided in a sensor body that detects the intruding object in the monitoring area to generate the stop signal, and the camera is used to check whether or not the sensor body is appropriately installed with respect to the monitoring area. However, this kind of safety device is often installed in a building, such as a factory, with a large number of workers. Hence a worker is apt to get into an angle of view of the camera to appear as a subject in a photographed image, which is problematic. When such a photographed image is displayed, the worker is at the risk of being personally identified.